Auger bit



K. KRONWALL Feb. 3, 1953 AUGER BIT Filed Sept. 8, 1947 FIG. 1

IN VEN TOR. Konsrontin Kronwoll Attorneys Patented Feb. 3, 1953 AUGER BIT Konstantin Kronwall, Winnetka, Ill., assignor to United Drill and Tool Corporation, Chicago, 11]., av corporation of Michigan Application September 8, 1947, Serial No. 772,865

4 Claims.

The present invention relates to auger bits and the principal object thereof is to provide an auger bit of rugged and economical construction.

Another object of the invention is to provide an auger bit of simple construction and arrangement that may be manufactured utilizing a minimum number of operations.

Further features of theinvention pertain to the particular arrangement of elements of the auger bit, whereby the above outlined and additional operating features thereof are attained.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification taken in connection with the accompanying drawing, in which Figure 1 is a front View of an auger bit embodying the present invention; Fig. 2 is a side view of the auger bit, shown in Fig. 1; Fig. 3 is an end view of the auger bit, shown in Figs. 1 and 2; Fig. 4 is a transverse sectional view of the auger bit taken in the direction of the arrows along the line 4-4 in Fig. 2; and Fig. 5 is a transverse sectional view of the auger bit taken in the direction of the arrows along the line 5-5 in Fig. 1.

Referring now more particularly to the drawing the auger bit I there illustrated, and embodying the features of the present invention, comprises an elongated longitudinally extending cylindrical shank H, carrying at its upper end a squared shank fixture l2 adapted to be received in a chuck or other tool and terminating in a forwardly tapered lower end 13 carrying an axially aligned screw point I4. Specifically, the extreme lower end of the tapered end 13 has a centrally disposed hole drilled therein which receives a stem I40, formed on the screw point l4, as illustrated in Fig. 5. After the stem [4a. of the screw point [4 is inserted into the hole mentioned, the two parts are brazed or welded together to provide an integral structure.

Also the tapered end 13 carries two oppositely directed laterally extending blades l and I6 adjacent to the screw point I l and rearwardly thereof. The blades l5 and 16 are formed integrally with the shank II and each blade extends laterally the same radius R from the axis of the shank II, as illustrated in Fig. 3. The blade I5 comprises a body, substantially rectangular in front view, and including a leading surface He and a trailing surface l5bterminating in an out-flared cutting head c. Likewise, the blade I6 comprises a body, substantially rectangular in front view, and including a leading surface I61 and a trailing surface lllb terminating in an out-flared cutting head its. Specifically, the cutting head I comprises an out-flared extension lip, into. which the surfaces I50, and 15b merge, that is provided with a cutting edge [5d and carries a forwardly projecting spur Hie. Likewise the cutting head I comp-rises an out-flared extension lip, into which the surfaces lea and l6b merge, that is provided with a cutting edge 16d and car ries a forwardly projecting spur the. Thus the cutting heads I50 and Ida are disposed on oppo-. site sides of the axis of the shank ll adjacent to the screw point it and rearwardly thereof.

Moreover, the two blades 15 and iii are arranged between two parallel planes spaced apart a distance established by the diameter of the shank l l, the upper ends of the trailing surfaces I52) and i617 of the respective blades 15 and 16 being disposed in the respective planes mentioned, as clearly illustrated in Figs. 2 and 4.

The two trailing surfaces 1% and 16b are respectively disposed in two spaced apart converging planes arranged tangential to two diametrically positioned converging lines on the surface of the tapered end l3 adjacent to the screw point 14, the trailing surfaces I512 and lfib merging into the surface of the tapered end l3 along the respective converging lines mentioned, as illustrated in Figs. 2 and 4. The leading surfaces Ilia and Ilia are both disposed intermediate the two converging planes mentioned, as illustrated in Figs. 2 and 4. Thus the leading surface of each blade is disposed below the trailing surface of the other blade; whereby two chip guiding channels are respectively defined in the bodies of the two blades and respectively extend rearwardly from the two cutting heads and outwardly from the screw point M.

In order to obtain most satisfactory results in regard to rugged construction and smooth operation of the auger bit Ii], it has been found the thickness T of the blades I5 and I6 should be approximately /4 to of the radius R, as indicated in Fig. 2, and that the width W of each of the cutting heads I50 and lBc should be at least of the radius R, as indicated in Fig. 3.

In the manufacture of the auger bit [0, it is preferable that the shank II, the squared shank fixture l2, and the blades I 5 and I6 be forged from a suitable piece of steel stock to approximate shape and then machined to the required dimensions, the centrally disposed hole being drilled in the extreme lower end of the tapered end l3. The screw point M is formed of steel stock and is machined to the required dimensions suited to quantity and quality production by ma-z chine methods.

While there has been described what is at pres- I ent considered to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein, and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

What is claimed is:

r 1. An integral auger bit comprising a longitudinally extending cylindrical shank terminating at the forward end thereof in two oppositely directed laterally extending substantially fiat blades, said two blades being arranged between two parallel planes spaced apart a distance established by the diameter of said shank and respectively terminating at the forward ends thereof in two forwardly directed cutting heads arranged on opposite sides of the longitudinal center line of said shank, each of said blades being provided with leading and trailing surfaces lying in substantially parallel planes and terminating in the respective one of said cutting heads, the leading surface of each of said blades being pitched at a slight leading angle with respect to the center line of said shank and toward the respective one of said cutting heads and cooperating with the forward end of said shank to define a chip-guiding channel extending rearwardly from the respective one of said cutting heads, and a screw point carried by the forward end of said shank between said two cutting heads and projecting forwardly along the longitudinal center line of said shank.

2. The auger bit set forth in claim 1, wherein each of said cutting heads includes an outwardly flared cutting edge and a forwardly projecting spur. l

3. The auger bit set forth in claim 1, wherein the trailing surfaces of said two blades are arranged tangential to the forward end of said shank at two substantially diametrically opposite points on the surface of the forward end of said shank.

4. The auger bit set forth in claim 1, wherein each of said blades extends laterally the same radial distance from the longitudinal center line of said shank the thickness of each of said blades is approximately A to of said radial distance, and the width of each of said cutting heads is at least of said radial distance.

KONSTANTIN KRONWALL.

REFERENCES CITED 'The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name' Date 124,089 Shepardson Feb. 27, 1872 149,637 Buchter Apr. 14, 1874 484,221 Moore Oct. 11, 1892 1,895,205 Prior Jan. 24, 1933 2,025,358 Maschek Dec. 24, 1935 7 2,055,144 Christian Sept. 22, 1936 FOREIGN PATENTS Number Country Date 18,548 Norway Mar. 27, 1908 193,786 Great Britain Mar. 1, 1923 194,542

Great Britain Mar. 15, 1923 

